x平方-6x+y平方+10y+34=0x^2-6x+y^2+10y+34=0,x^2-6x+9+y^2+10y+25=0,(x-3)^2+(y+5)^2=0x-3=0,y+5=0,x=3,y=-5所以x平方+3x除以2xy+2y=(x^2+3x)/(2xy+2y)=(9+9)/(-30-10)=18/(-40)=-9/20